Dementia is a loss of brain function that occurs with certain diseases. It affects memory, thinking, language, judgment, and behavior.
See also: Alzheimer's disease
Chronic brain syndrome; Lewy body dementia; DLB; Vascular dementia; Mild cognitive impairment; MCI
Causes, incidence, and risk factors
Most types of dementia are nonreversible (degenerative). Nonreversible means the changes in the brain that are causing the dementia cannot be stopped or turned back. Alzheimer's disease is the most common type of dementia.
Lewy body disease is a leading cause of dementia in elderly adults. People with this condition have abnormal protein structures in certain areas of the brain.
Dementia also can be due to many small strokes. This is called vascular dementia.
The following medical conditions also can lead to dementia:
- Huntington's disease
- Multiple sclerosis
- Infections that can affect the brain, such as HIV /AIDS and Lyme disease
- Parkinson's disease
- Pick's disease
- Progressive supranuclear palsy
Some causes of dementia may be stopped or reversed if they are found soon enough, including:
- Brain injury
- Brain tumors
- Chronic alcohol abuse
- Changes in blood sugar, sodium, and calcium levels (see: Dementia due to metabolic causes)
- Low vitamin B12 levels
- Normal pressure hydrocephalus
- Use of certain medications, including cimetadine and some cholesterol-lowering medications
Dementia usually occurs in older age. It is rare in people under age 60. The risk for dementia increases as a person gets older.
Dementia symptoms include difficulty with many areas of mental function, including:
- Emotional behavior or personality
- Cognitive skills (such as calculation, abstract thinking, or judgment)
Dementia usually first appears as forgetfulness.
Mild cognitive impairment is the stage between normal forgetfulness due to aging and the development of dementia. People with MCI have mild problems with thinking and memory that do not interfere with everyday activities. They are often aware of the forgetfulness. Not everyone with MCI develops dementia.
Symptoms of MCI include:
- Difficulty performing more than one task at a time
- Difficulty solving problems or making decisions
- Forgetting recent events or conversations
- Taking longer to perform more difficult mental activities
The early symptoms of dementia can include:
- Difficulty performing tasks that take some thought, but that used to come easily, such as balancing a checkbook, playing games (such as bridge), and learning new information or routines
- Getting lost on familiar routes
- Language problems, such as trouble finding the name of familiar objects
- Losing interest in things you previously enjoyed, flat mood
- Misplacing items
- Personality changes and loss of social skills, which can lead to inappropriate behaviors
As the dementia becomes worse, symptoms are more obvious and interfere with the ability to take care of yourself. The symptoms may include:
- Change in sleep patterns, often waking up at night
- Difficulty doing basic tasks, such as preparing meals, choosing proper clothing, or driving
- Forgetting details about current events
- Forgetting events in your own life history, losing awareness of who you are
- Having hallucinations, arguments, striking out, and violent behavior
- Having delusions, depression, agitation
- More difficulty reading or writing
- Poor judgment and loss of ability to recognize danger
- Using the wrong word, not pronouncing words correctly, speaking in confusing sentences
- Withdrawing from social contact
People with severe dementia can no longer:
- Perform basic activities of daily living, such as eating, dressing, and bathing
- Recognize family members
- Understand language
Other symptoms that may occur with dementia:
- Swallowing problems
Signs and tests
A skilled health care provider can often diagnose dementia by performing a physical exam and asking questions about the person's medical history.
The physical exam will include a neurological exam. Tests to check mental function will be done. This is called a mental status examination.
Other tests may be ordered to determine whether other problems could be causing dementia or making it worse. These conditions include:
- Brain tumor
- Chronic infection
- Intoxication from medications
- Severe depression
- Thyroid disease
- Vitamin deficiency
The following tests and procedures may be done:
- B12 level
- Blood ammonia levels
- Blood chemistry (chem-20)
- Blood gas analysis
- Cerebrospinal fluid (CSF) analysis
- Drug or alcohol levels (toxicology screen)
- Electroencephalograph (EEG)
- Head CT
- Mental status test
- MRI of head
- Thyroid function tests
- Thyroid stimulating hormone level
Treatment depends on the condition causing the dementia. Some people may need to stay in the hospital for a short time.
Stopping or changing medications that make confusion worse may improve brain function.
There is growing evidence that some kinds of mental exercises can help dementia.
Treating conditions that can lead to confusion often greatly improve mental functioning. Such conditions include:
- Congestive heart failure
- Decreased blood oxygen (hypoxia)
- Heart failure
- Nutritional disorders
- Thyroid disorders
Medications may be needed to control behavior problems caused by a loss of judgment, increased impulsivity, and confusion. Possible medications include:
- Antipsychotics (haloperidol, risperidone, olanzapine)
- Mood stabilizers (fluoxetine, imipramine, citalopram)
- Stimulants (methylphenidate)
Certain drugs may be used to slow the rate at which symptoms worsen. The benefit from these drugs is often small, and patients and their families may not always notice much of a change.
- Donepezil (Aricept), rivastigmine (Exelon), galantamine (Razadyne, formerly called Reminyl)
- Memantine (Namenda)
A person's eyes and ears should be checked regularly. Hearing aids, glasses, or cataract surgery may be needed.
Psychotherapy or group therapy usually does not help because it may cause more confusion.
For information on how to take care of a loved one with dementia, see: Dementia - home care
People with mild cognitive impairment do not always develop dementia. However, when dementia does occur, it usually gets worse and often decreases quality of life and lifespan.
Complications depend on the cause of the dementia, but may include the following:
- Abuse by an overstressed caregiver
- Increased infections anywhere in the body
- Loss of ability to function or care for self
- Loss of ability to interact
- Reduced lifespan
- Side effects of medications used to treat the disorder
Calling your health care provider
Call your health care provider if:
- Dementia develops or a sudden change in mental status occurs
- The condition of a person with dementia gets worse
- You are unable to care for a person with dementia at home
Most causes of dementia are not preventable.
Quitting smoking and controlling high blood pressure and diabetes can help you reduce your risk of vascular dementia. This is dementia caused by a series of small strokes. Eating a low-fat diet and exercising regularly may also reduce the risk of vascular dementia.
Burns A, Iliffe S. Alzheimer's disease. BMJ. 2009;338.
DeKosky ST, Kaufer DI, Hamilton RL, Wolk DA, Lopez OL. The dementias. In: Bradley WG, Daroff RB, Fenichel GM, Jankovic J, eds. Bradley: Neurology in Clinical Practice. 5th ed. Philadelphia, Pa: Butterworth-Heinemann Elsevier; 2008:chap 70.
Knopman DS. Alzheimer’s disease and other dementias. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 409.
Peterson RC. Clinical practice. Mild cognitive impairment. N Engl J Med 2011 Jun 9;364(23):2227-2234.
Qaseem A, et al., American College of Physicians/American Academy of Family Physicians Panel on Dementia. Current pharmacologic treatment of dementia: a clinical practice guideline from the American College of Physicians and the American Academy of Family Physicians. Ann Intern Med 2008 Mar 4;148(5):370-8.
Last reviewed 9/26/2011 by Luc Jasmin, MD, PhD, Department of Neurosurgery at Cedars-Sinai Medical Center, Los Angeles, and Department of Anatomy at UCSF, San Francisco, CA. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
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